title: Plasma biomarkers of liver injury and inflammation demonstrate a lack of apoptosis during obstructive cholestasis in mice.
abstract: Cholestasis is a pathological common component of numerous liver diseases that results in hepatotoxicity, inflammation, and cirrhosis when untreated. While the predominant hypothesis in cholestatic liver injury remains hepatocyte apoptosis due to direct toxicity of hydrophobic bile acid exposure, recent work suggests that the injury occurs through inflammatory necrosis. In order to resolve this controversy, we used novel plasma biomarkers to assess the mechanisms of cell death during early cholestatic liver injury. C57Bl/6 mice underwent bile duct ligation (BDL) for 6-72 h, or sham operation. Another group of mice were given d-galactosamine and endotoxin as a positive control for apoptosis and inflammatory necrosis. Plasma levels of full length cytokeratin-18 (FL-K18), microRNA-122 (miR-122) and high mobility group box-1 protein (HMGB1) increased progressively after BDL with peak levels observed after 48 h. These results indicate extensive cell necrosis after BDL, which is supported by the time course of plasma alanine aminotransferase activities and histology. In contrast, plasma caspase-3 activity, cleaved caspase-3 protein and caspase-cleaved cytokeratin-18 fragments (cK18) were not elevated at any time during BDL suggesting the absence of apoptosis. In contrast, all plasma biomarkers of necrosis and apoptosis were elevated 6 h after Gal/End treatment. In addition, acetylated HMGB1, a marker for macrophage and monocyte activation, was increased as early as 12 h but mainly at 48-72 h. However, progressive neutrophil accumulation in the area of necrosis started at 6h after BDL. In conclusion, these data indicate that early cholestatic liver injury in mice is an inflammatory event, and occurs through necrosis with little evidence for apoptosis.
authors.affiliation: Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Woolbright
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Antoine
authors.forename: Rosalind E
authors.initials: RE
authors.lastname: Jenkins
authors.forename: Mary Lynn
authors.initials: ML
authors.lastname: Bajt
authors.forename: B Kevin
authors.initials: BK
authors.lastname: Park
authors.forename: Hartmut
authors.initials: H
authors.lastname: Jaeschke
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D017209:Apoptosis; D001647:Bile Acids and Salts / Q000009:adverse effects / Q000378:metabolism; D001652:Bile Ducts / Q000601:surgery; D015415:Biomarkers / Q000097:blood*; D053148:Caspase 3 / Q000097:blood; D002779:Cholestasis / Q000097:blood* / Q000473:pathology; D005688:Galactosamine / Q000009:adverse effects; D024243:HMGB1 Protein / Q000097:blood; D022781:Hepatocytes / Q000473:pathology; D007249:Inflammation / Q000473:pathology; D053538:Keratin-18 / Q000097:blood; D008026:Ligation; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008107:Liver Diseases / Q000097:blood* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000097:blood; D009336:Necrosis / Q000097:blood / Q000473:pathology; D009504:Neutrophils / Q000473:pathology
chemical_list: D001647:Bile Acids and Salts; D015415:Biomarkers; D024243:HMGB1 Protein; D053538:Keratin-18; D035683:MicroRNAs; C544354:Mirn122 microRNA, mouse; D005688:Galactosamine; D000410:Alanine Transaminase; C505409:Casp3 protein, mouse; D053148:Caspase 3
keywords: ALT; Apoptosis; BDL; Bile duct ligation; Biomarkers; Cytokeratin-18; DAMP; FL-K18; GCDC; Gal/End; H&E; HMGB1; High mobility group box-1; ICAM-1; TNF-α; alanine aminotransferase; bile duct ligation; cK18; caspase-cleaved cytokeratin-18 fragment; damage associated molecular pattern; full length cytokeratin-18; galactosamine/endotoxin; glycochenodeoxycholate; hematoxylin and eosin; high mobility group box 1; intercellular adhesion molecule-1; miR-122; microRNA-122; tumor necrosis factor-alpha